A collapsed lung, medically termed a pneumothorax, occurs when air leaks into the space between the lung and the chest wall. This air accumulation creates pressure on the outside of the lung, causing it to deflate partially or completely. Because the lung cannot fully expand under this pressure, the body’s ability to take in oxygen and expel carbon dioxide is compromised. It requires immediate attention to prevent severe complications.
The Mechanics of Lung Collapse
The normal function of the lung depends on a delicate pressure balance maintained within the chest cavity. The lungs are encased in a double-layered membrane known as the pleura, and the tiny gap between these layers is the pleural space. This space typically maintains a negative pressure relative to the air inside the lungs and the outside atmosphere. This negative pressure acts like a vacuum, keeping the lung inflated and held tightly against the chest wall as the chest expands during inhalation.
When a pneumothorax occurs, this vacuum seal is broken by a breach in either the outer chest wall (parietal pleura) or the lung’s surface (visceral pleura). Air rushes into the pleural space. The lung tissue itself has a natural elasticity, causing it to recoil inward like a deflating balloon once the opposing external pressure is gone. The degree of collapse depends on the volume of air that has entered the pleural space.
In cases of traumatic injury, such as a stab wound or fractured rib, the air enters directly from the outside or through the damaged chest wall tissue. Spontaneous collapses happen when a small, air-filled blister on the lung surface, called a bleb or bulla, ruptures internally. If the air continues to build up and cannot escape, it can lead to a tension pneumothorax. This condition is a life-threatening emergency where pressure pushes the heart and other structures to the opposite side of the chest.
Recognizing the Signs and Underlying Causes
The most common and immediate symptom of a collapsed lung is the sudden onset of sharp, one-sided chest pain. This pain often intensifies with a deep breath or a cough because the inflamed pleural layers rub against one another. A person will also experience shortness of breath, which can range from mild to severe depending on the extent of the collapse.
Other symptoms include a rapid heart rate and easy fatigue. In more significant collapses, the lack of oxygen may cause the skin, lips, or nail beds to take on a bluish tint (cyanosis). The severity of these signs usually correlates directly with the amount of lung that has collapsed and any pre-existing lung conditions.
Pneumothoraces are broadly categorized by their cause, which can be traumatic or spontaneous. Traumatic causes involve direct injury to the chest, such as from car accidents, falls, or penetrating wounds. Spontaneous collapses occur without external trauma and are subdivided into primary and secondary types.
Primary spontaneous pneumothorax often affects tall, thin males between the ages of 10 and 30 and is strongly linked to cigarette smoking. This type is generally due to the rupture of apical blebs on the lung’s surface. Secondary spontaneous pneumothorax happens in people with underlying lung diseases, where the tissue is already compromised and more prone to rupture. Conditions such as Chronic Obstructive Pulmonary Disease (COPD), cystic fibrosis, asthma, and certain infections greatly increase this risk.
Restoring Lung Function
Diagnosis of a collapsed lung typically begins with a physical exam, where a healthcare provider may note decreased or absent breath sounds on the affected side of the chest. A chest X-ray is the standard tool to confirm the presence of air in the pleural space and estimate the size of the collapse. In some instances, a Computed Tomography (CT) scan is used to gain a more detailed image of the lung tissue and identify any underlying blebs or bullae.
Treatment is determined by the size of the pneumothorax and the patient’s symptoms. For a very small collapse with minimal symptoms, a doctor may opt for observation, sometimes with supplemental oxygen, allowing the body to naturally reabsorb the excess air over several days or weeks. For larger or more symptomatic collapses, the goal is to actively remove the trapped air to permit the lung to re-expand immediately.
A common procedure is needle aspiration, where a hollow needle is inserted between the ribs to withdraw the air with a syringe. If this is insufficient or the air leak is ongoing, a chest tube is inserted into the pleural space. This tube is connected to a one-way valve system or a suction device that continuously pulls the air out.
In cases of recurrent pneumothorax or a persistent air leak, surgical intervention may be needed to prevent future collapses. Procedures like video-assisted thoracoscopic surgery (VATS) are used to visualize the lung and seal the air leaks. A technique called pleurodesis may be performed, which involves irritating the pleural layers to make them stick together.